Direct fuel feeding system



Dec. 29, 1931. w. EDWARDS 1,838,137

DIRECT FUEL FEEDING SYSTEM Filed 001:. 3, 1928 2 Sheets-Sheet 1 j/f/"ZAM@WWQMMF Dec. 29, 1931. w EDWARDS 1,838,137

DIRECT FUEL FEEDING SYSTEM Filed Oct. 3,. 1928 2 Sheets-Sheet 2 35 35Zfizfiaxs I fwyev zzar WMM E z/zzzlmdzza ms Patented Dec. 29, 1931UNITED STATES WILLIAM .A. EDWARDS, OF CHICAGO, ILLINOIS DIRECT FUELFEEDING SYSTEM Application filed October 3, 1928.

The purpose of this invention is to provide a fuel feeding system foraninternal combustion engine of an automobile or other engine operatedvehicle, by which the fuel may be fed to the engine by engine suctiondirectly from a main fuel tank which may be carried in the usuallypreferred position at the rear end of thevehicle or at other positionrelatively distant of the engine. It consists in lo the elements andfeatures of construction shown and described as indicated in the claims.

In the drawings:

Figure 1 is a partly sectional diagrammatic View showing the relativepositions on the vehicle and with respect to the engine of the severalparts of the fuel feeding system embodying the invention.

Figure 2 is a detail elevation on an enlarged scale of the parts of thesystem which are located on and adjacent to the engine body.

Figure 3 is a section at the line 33 on F igure 2.

Figure 4; is a section at the line 4-4 on Fig- 2 ure 1.

Figure 5 is a vertical fore-and-aft section through the main fuel supplytank shown in Figure 1 as carried at the rear of the vehicle, sectionbeing made at a plane cutting through the center of aprimary fuelmixture forming apparatus which is located in said main fuel tank.

Upon considering the drawings in a comprehensive manner it will be seenthat there is mounted on the engine a construction of the nature of amixing chamber having the air inlet controlled by an air valve which isnormally seated by a spring and adapted to be 4.0 opened by enginesuction.

This structure comprises a fuel mixture passage leading to the. engineintake, said structure being mounted on the intake manifold and arrangedfor connection with a .pri-

mary fuel mixture pipe discharging in the air stream flowing to theintake manifold when the air valve mentioned is opened by enginesuction. This engine-supported part of the structure comprises also adash pot hav- 5o ing a plunger connected by a lever with the Serial No.309,942.

air valve for slowing down both the opening and closing movements ofthat valve.

It will vbe noted that the primary fuel mixture pipe leads to the enginefor delivering primary fuel mixture into the air stream, as stated, froma'primary fuel-mixture-forming apparatus which is located in the mainfuel tank at the rear of the vehicle, said fuel mixture formingapparatus comprising a governed level fuel chamber of the character of acommon carbureter float bowl, which derives fuel by gravity flow fromthe main fuel tank within which said fuel chamber is located.

It will be further noted that the expedient by which this fuel mixtureforming apparatus is positioned within the main fuel tank consists inproviding a cylindrical casing which is intruded in the main fuel tankfrom above the same through an aperture provided for that purpose, saidcasing being closed at both bottom and top, the top closure member beingoutside the main fuel tank, and the lower end portion of said casingconstituting the governed level fuel chamber, which derives fuel througha bottom opening by gravity. from the main tank. And it will be notedthat the primary fuel mixture conduit consists of a pipe which leadsinto said casing through the top and extends down into proximity to thegoverned level of the governed level fuel chamber, and thence up to thetop of the casing from which it emerges for extending forward to theengine.

And it will be noted also that for discharge of fuel into this primaryfuel mixture pipe there are provided two ducts leading from the governedlevel chamber, one of which extends up through the top of the casing,and is reflexed for discharging downwardly into the downwardly leadinglimb of the pipe, which thereby becomes a fuel mixture pipe, the otherof said ducts projecting for discharge of' fuel into said pipe at thelower end of the upwardly extending limb of said pri- 5 mary f-uelmixture pipe.

Referring to the drawings for describing the construction in detail:-The engine body is indicated at A, with the intake manifold at A Themain fuel tank is shown at B at the rear of the vehicle. C representsthe engine exhaust pipe, in which the muffler is shown at C Aconstruction of the nature of a pipe fitting formed for mounting on theengine body for communication with the intake manifold is showncomprising apart, 20, hereinafter referred to as the final fuel mixtureconduit, which is in Venturi form having its flaring entrance member, 20bell-shaped, to form what is hereinafter referred to as a bell mouth,said fitting being extended from said bell mouth to form an air inletchamber, 22, having an air valve, 24, held normally seated by a spring,25, coiled around the stem, 26, of said valve, and reacting against athreaded sleeve, 27, which is screwed into the back or under side of theair chamber at a boss, 22 provided for that purpose, the stem of thevalve being extended through the sleeve, and said sleeve beingadjustable at its mounting in the boss for adjusting the tension of thespring to adapt the valve to begin to open at a predetermined degree ofengine suction, and to open proportionately to the increase of suctionbevond said predetermined degree. ldounted adjacent to the fitting infixed position with respect thereto, there is provided a dash potchamber, 28, having its plunger, 29, connected by a lever, 30, with theair valve stem, 26, so that the dash pot resistance operates to opposeand slow down the movement of the air valve either in opening orclosing.

Within the bell mouth, 20, of the Venturi portion, 20, of the fitting,there is fixedly positioned a tapered approximately conical airdischarge terminal, 21, which fits at its wider end tightly in the bellmouth entrance, its narrower end, which may be referred to as the airnozzle or jet end, standing concentrically in the venturi proximate tothe constriction thereof annularly spaced from the inner wall of theventuri at that point.

The bell mouth form of the entrance end of the venturi, in conjunctionwith the conically tapered, and also as shown, slightly exteriorlyconcave-form of the air nozzle, 21, creates a cavity within said bellmouth and around the air nozzle, into which the primary fuel mixture isdischarged by the primary fuel mixture pipe, 50, which is connected atone side of the bell mouth, as seen at 52.

Referring to the construction of the primary fuel mixture formingapparatus and main fuel tank, as shown in Figure 5, it will be notedthat the pipe which becomes the primary fuel mixture pipe at its extentthrough the primary fuel mixture forming apparatus, has its inlet, asshown at 30, at a point forward of the muflier, C through which saidpipe extends, as indicated in dotted line in Figure 1, continuing fromthe rear end of the muffler rearward past the under side of the mainfuel tank, B, behind which said pipe extends upwardly, and thenceforwardly for connection, as shown at 35, with the upper end cap, 41, ofthe tubular casing, 40, which, as above mentioned, isintruded downthrough the top of the fuel tank, B, where an opening furnished with aflanged collar, 40, is provided for admitting said casing and seatingits cap, 41.

The bottom cap, 42, of the casing has an inlet port, 43, controlled by avalve, 44, whose stem extends up into the casing and is connected withafloat, 44", which governs the level to which the liquid entering bygravity from the main fuel tank into the casing can rise in the casing;whereby the casing at its lower part becomes a governed level fuelchamber. From the aperture in the cap, 41, at which the pipe, 30, isconnected, as seen at 35 said aperture extending in angular form andopening downwardly from the cap, there is connected a pipe member, 32,constituting a down limb of the conduit of which the pipe, 30, is theinitial part. Said pipe, 32, extends downwardly approximately to thegoverned liquid level above the float, 45, and is there flexed to extendhorizontally above the float a short distance, and connected by an elbowfitting, 33, with an upwardly extending limit, 34, which extends inspiral form up through the casing, 40, and is connected at its upper endat an aperture, 36, through the cap plate, 41, and opening forwardly andhorizontally for connection with a pipe member, 38, which constitutes acontinuation of the primary fuel mixture conduit and leads forwardly tothe structure above described mounted at the engine intake manifold,where said pipe is connected, as above pointed out, at the aperture, 52,for discharging into the air stream entering the engine past the airvalve, 24, through the air chamber, 22.

Referring to Figure 5 there may be seen a fuel duct, 45, which leadsfrom the lower part of the governed level fuel chamber in the bottom ofthe casing, 40, with horizontal deflection for entering the elbowfitting, 33, through which it extends liquid-tight, and within saidelbow fitting is deflected upwardly for discharge upwardly in the uplimb, 34, of the primary fuel mixture conduit. And there will be seenalso leading similarly from the lower part of the governed level fuelchamber a pipe, 46, extending up in the easing, 40, and connected with apassage, 48, in the cap, 41, at the upper end of which there is provideda nozzle terminal, 49, creating a 180 bend which affords downwarddischarge into the upper end of the fuel mixture conduit pipe member,32.

It will be noted that while the fuel discharge duct, 45, has itsdischarge directly in the lower entrance end of the up limb, 34, wheresaid pipe is of full diameter, a different construction is provided atthe discharge of the fuel duct, 46, where its return bend through thepipe, 38, to the engine.

nozzle discharges into the down limb, 32, there being formed at theentrance of said down limb a small venturi, 47, proximate to theconstriction whereof, the return bend nozzle, 49, terminates for fueldischarge.

The purpose of the provision of two fuel ducts discharging in the airpipe for forming a primary fuel mixture is to adapt the construction toyield primary fuel mixture of suitably varying richness under varyingconditions of engine operation. It may be understood that under engineoperating conditions which developa high degree of suction at theentrance of the primary fuel.mixture pipe to the air stream, with whichit is to blend to form the final fuel mixture which serves the engine,the depression at the discharge of the duct 45, in the up limb, 34, willbe suiiicientto take the fuel from the duct, 45, and cause it to besuitably intermixed with the air as it passes through the spiral extentof said up limb, and thence on But that under such conditions of lowengine suction, the depression in the pipe, 30, at the point'at whichthe fuel duct, 46, opens for discharge of fuel into the down limb, 32,in the absence of the venturi, 47,, will not be sufficient to lift thefuel from the governed level chamber through the height of the main fueltank, 13, and cause the fuel to be discharged into said down limb, 32.And it may be understood'that upon increase of the suction, causingincrease of the amount of fuel which will be taken through the duct, 45,such increase will continue in diminishing degree, as the suctioncontinues to increase, a point being finally reached at which furtherincrease of the suction does not ap. preciably increase the amount offuel taken; and that at some stage in the increase of suction, thedepression at the discharge of the pipe, 46, in the down limb, 32, willbe sufficient to lift the fuel through the duct, 46, from the governedlevel chamber to said discharge point; and that the provision of theventuri, 47, at this point causes the delivery of fuel through the duct,46, at a lower de- 50\gree of engine suction than would be the case inthe absence of such a venturi. I have ascertained that the dimensions ofthe several parts affecting the flow capacity of the duct, 45, the flowcapacity of the duct, 46', and the acceleration of the air flow by theventuri, 47 may be designed in accordance with demonstrated rules tocause the total flow of fuel through both ducts, 45, and 46,notwithstanding at part of the time fuel is flowing only through theduct, 45, and part of the time increasingly through the duct, and part-of the time gradually and increasingly through the duct, 32, to varysuitably in relation to the variation of engine suction under differentrunning conditions, so as to cause the primary fuel mixture to be ofproper for the primary fuelmixture derived through the pipe, 50, whichis ample at the zone of the entrance to the pipe, 50, and diminishes incross section toward the relatively small annular discharge. at theVenturi constriction,-

has been found of very material advantage in obtaining the desirablegradual change in the depression at that point instead of the relativelyabrupt changes which are unavoidable when the form of the Venturientrance and the air nozzle discharge thereinto are of the more commonsimple frusto-conical form.

The arrangement of the air valve, 24, and the dash pot, 29, relativelyto each other for facilitating the employment of lever connectionbetween the two, and the employment of such connection adapted to makethe plunger movement a small fraction of the valve movement, 'as bymaking the lever arm connected to the plunger several times the lengthof the lever arm connected to the valve, has been found of verysubstantial advantage in causing the valve-opening movement to becorrectly and reliably related to the engine suction, avoiding abruptchanges in the air supply which tend to prevent uniformity in the fuelmixture because the ertia of the liquid fuel, tends to prevent itresponding to abrupt changes in the air flow which producescorresponding abrupt changes in the depression at the fuel nozzle.

The spiral form of the fuel mixture pipe, 34, while operating slightlyfor retardment of the flow, is chiefly important by reason of the spiralmovement of the current through it i which this form compels, and whichcauses a centrifugal action of the liquid particles more or lesscompletely atomized, causing their impact upon the walls of the pipe.which results in deposit of the liquid, which, flowing slowly down thespiral wall, is exposed to the air current rushing past it and operatingto wipe it up, with the effect of more complete atomization, the delayin view of the circumstance that the air current has been pre -heatedand that the walls of the spiral pipe are corresponding heated, causingvaporization of an important percentage of the liquid fuel which wouldotherwise be only atomized by the action of the air current.

I claim 1. In a direct fuel feed system for motor vehicles, an internalcombustion engine having an air supply passage to the engine intake,

a main fuel supply tank mounted on the vehicle remotely from the engineand a primary-fuel-mixture-forming apparatus located proximate the tankand comprisin a governed level fuel chamber, a discharge uct therefromand a pipe into which it discharges for forming a primary mixture, saidpipe leading from its'intake rearwardly into proximity to the governedlevel fuel chamber for receiving fuel discharge from said chamber andhaving its course rearwardly from the inlet to the governed level fuelchamber extending through a portion of the engine exhaust passage alongthe exhaust pipe and through the muflier; whereby the air currentthrough said pipe into which the fuel is discharged is heated forvaporizing said fuel at its discharge.

2. In a direct fuel feed system for motor vehicles, an internalcombustion engine having an air supply passage to the engine intake, amain fuel suppply tank mounted on the Vehicle remotely from the vehicle,a primaryfuel mixture forming apparatus located proximate the tank andcomprising a governed level fuel chamber, a discharge duct therefrom anda primary fuel mixture pipe into which it discharges, said primary fuelmixture pipe having its course from its inlet rearwardly to the governedlevel fuel chamber extending through the mufiier and having its returncourse from the governed level fuel chamber extending forwardly to theengine for discharge with the air entering the air supply passage of theengine intake, and having at a part of its said return course a. heatingacket connected with the engine exhaust 3. In a direct fuel feed systemfor motor vehicles. an internal combustion engine having an air supplypassage to the engine intake, a main fuel supply tank mounted on thevehicle remotely from the engine and a primary-fuel-mixtute-forming airpassage located within the tank and. comprising a governed level fuelchamber, a discharge duct therefrom and a primary fuel mixture pipe intowhich it'discharges, said primary fuel mixture pipe having its coursefrom its air inlet rearwardly to thegoverned level fuel chamber leadingthrough the muflier and having its course from its emergence, from themain tank forwardly to the engine for discharge with the air enteringthe air supply passage to the engine intake and having at a part of itssaid-return course a heating jacket connected with the engine exhaustpipe.

. cated proximate-the fuel tank comprising a '4. Ina direct fuel feedingsystem for mogoverned level fuel chamber arranged to derive fuel bygravity from the tank, a primary air pipe having atmosphere intake at apoint governed level fuel chamber having a fuel discharge duct extendingfor discharge in the upwardly extending limb of the primary air pipe forproducing a primary fuel mixture; whereby said primary pipe conductspreheated air to the point at which fuel is discharged thereinto forproducing said primary fuel mixture, and said mixture is rendered inpart vaporous at its formation and at its discharge in the main airpipe.

5. In a fuel feeding system for motor vehicle internal combustionengines, in combination with a main fuel supply tank mounted on thevehicle relatively distant from the engine, a main air supply pipeleading to the engine intake; a primazy-fuel-mixture-forming apparatusconsisting of a governed level fuel chamber, a primary fuel mixtureconduit terminating for delivery of a primary fuel mixture in the airstream flowing toward the engine through the main air supply pipe, andfuel discharge ducts from the governed level chamber discharging intothe primary fuel mixture conduit, one near the governed level of saidchamber and another at a substantial distance above said level.

6. In the construction defined in claim 5, the primary fuel mixtureconduit having a Venturi constriction at the location of the higherleveldischarge into said conduit.

7. In the construction defined in claim 5, the higher level dischargebeing antecedent in the course of the air flow through the conduit, tothe lower level discharge.

8. In the construction defined in claim 5, the higher level dischargebeing antecedent in the course of air flow through the conduit, to thelower level discharge, the conduit being flexed in spiral form at theupwardly extending part following said lower level discharge.

9. In a fuel feeding system for motor vehicles in combination with amain fuel supply tank, a primary-fuel-mixture-forming apparatusconsisting of a governed level fuel chamber arranged to derive fuel bygravity flow from. the tank, a discharge duct therefrom and a primaryfuel mixture pipe into which said ,duct discharges for forming therein aprimary fuel mixture, said pipe having a portion of'its extent flexed inspiral form for promotingtheagitation and thereby the intermixture ofthe air and fuel flowing through said pipe.

10. In the construction defined in claim 9, the spirally formed portionbeing an upwardly extending portion of said primary mixture onduit. 1

11. In a fuel supply system for internal combustion engines, a primaryfuel mixtureforming device comprising in combination with a fuelchamber, a fuel discharge duct leading therefrom, a pipe within whichthe duct terminates for discharge and mixture of the fuel with the aircurrent through said pipe, said air pipe having a substantial portion ofits length extending spirally for causing centrifugal action of theliquid particles carried by the air current, causing them to impinge onthe wall of the pipe.

12. In a fuel feeding system for internal combustion engines, incombination with the engine exhaust conduit and fuel supply tank, aprimary-fuel-mixture-forming apparatus located proximate to the tank andcomprising a governed level fuel chamber, a discharge duct therefrom anda primary fuel mixture pipe into which'it discharges, said primary fuelmixture pipe having its course from its inlet to the governed level fuelchamber extending through the exhaust muffler and having its returncourse from the governed level fuel chamber extending for discharge withthe air entering the air supply passage of the engine intake, and havingat a part of its said return course a heating jacket connected with theengine exhaust conduit.

13. In a fuel feeding system for internal combustion engines, incombination with the engine exhaust conduit and fuel supply tank, aprimary-fuel-mixture forming air passage located Within the tank andcomprising a governed level fuel chamber, a discharge duct therefrom anda primary fuel mixture pipe into which it discharges, said primary fuelmixture pipe having its course from its air inlet to the governed levelfuel chamber leading through the exhaust muflier, and having its coursefrom its emergence from the main tank trending toward the engine fordischarge with the air entering the air supply passage to the engineintake, and having at a part in said return course a heating jacketconnected with the engine exhaust conduit.

14. In a fuel feeding system for internal combustion engines, incombination with the engine exhaust conduit and main fuel supply tank, aprimary-fuel-mixture-forming apparatus located proximate the tank andcomprising a governed level fuel chamber arranged to derive fuel bygravity from the tank, a primary air pipe having atmosphere intake at apoint remotely forward of the tank, said pipe extending along theexhaust conduit and through the exhaust mufller to the vicinit of thefuel tank, and proximate to the liquid level of said governed level fuelchamber, said pipe thence turning upwardly and leading forwardly to theengine for discharge in the main air supply passage of the engine; thegoverned level fuel chamber having a fuel dischargeduct extending fordischarge in the upwardly extending limb. of said primary air pipe forproducing a primary fuel mixture; whereby said primary pipe conductspre-heated air from the point at which fuel is discharged thereinto forproducing said primary fuel mixture, and said mixture is rendered inpart vaporous at its formation and at its discharge in the main airpipe.

In testimony whereof, I have hereunto set my hand at Chicago, Illinois,this 29th day of September, 1928.

WILLIAM A. EDWARDS.

